Abstract:

A method for the simultaneous determination of triclopyricarb and oxadiargyl residues in vegetative foods was developed using QuEChERS-high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with acidic acetonitrile, and then cleaned up by primary secondary amine (PSA) and NH₂ adsorbents. The analytes were separated on a C₁₈ column with isocratic gradient elution of 0.1%(v/v) formic acid in water (containing 2 mmol/L ammonium acetate)-methanol (2:8, v/v) at a flow rate of 0.25 mL/min. The mass spectrometry was carried out with electrospray positive ion source (ESI⁺) in multiple reaction monitoring (MRM) mode. The qualitative analysis was based on the retention times and characteristic ion pairs consisting of one parent ion and two fragment ions, and the quantitative analysis was carried out by matrix-matched external standard method. The results showed that calibration curves had good linearities for triclopyricarb and oxadiargyl, and the correlation coefficients (r²) were larger than 0.996; the limits of quantification (LOQs, S/N≥10) of triclopyricarb in the six matrices (grape, raisin, potato, rice, tomato, rapeseed) were 0.5 μg/kg, and the LOQs of oxadiargyl in the six different matrices were 1.0 μg/kg. When the articles were spiked with three levels of analytes (1×LOQ, 2×LOQ and 10×LOQ), the recoveries of triclopyricarb were from 71.6% to 112.1% with the RSDs from 2.6% to 12.1%; and the recoveries of oxadiargyl were from 77.6% to 118.8% with the RSDs from 3.6% to 14.3%. The method is highly effective, sensitive, accurate, and is suitable for the monitoring of triclopyricarb and oxadiargyl in vegetative foods.

Key words: high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), oxadiargyl, QuEChERS, triclopyricarb, vegetative foods